The present invention relates generally to forming man-made fibers and particularly to forming a mineral wool.
Mineral wool is a fiber made from natural or synthetic minerals or metal oxides. Industrial applications of mineral wool include thermal insulation, filtration, and soundproofing.
The process of manufacturing mineral wool generally involves combining a number of ingredients, also referred to as components or starting materials, into a furnace, such as a cupola. Conventional ingredients include blast furnace slag, virgin minerals and coke as a fuel. One manufacturing technique involves heating the furnace to a high temperature, for example, in the range of 1400-2000° C., and preferably 1600° C., phase-changing, or melting, the ingredients to form a liquid, and blowing a stream of air or steam through the liquid using a wheeled spinner as is well known in the art. The final product is a mass of fine, intertwined, nonwoven fibers.
In conventional mineral wool, components are typically selected and proportioned in a way that maintains a target acid-to-base (A/B) ratio of the constituent fibers. The A/B ratio is a key parameter because it indicates fiber solubility, or how readily the fibers dissolve in bodily fluids, such as blood and saliva. This is an important characteristic for reasons having to do with human health, because these materials are likely to come into contact with humans as a result of their use in building construction materials.
Examples of virgin minerals conventionally used as starting materials in mineral wool production are quartzite and granite. In some cases, the virgin minerals constitute a relatively high proportion of the starting materials by dry weight. The use of such virgin minerals in the production of mineral wool is currently less desirable due to a trend in the building construction industry toward conservation of resources and recycling of materials.